Patterson Function from Low-Energy Electron Diffraction Measured Intensities and Structural Discrimination

TL;DR

This paper demonstrates how surface Patterson functions derived from low-energy electron diffraction intensities can effectively discriminate between different surface structural models, simplifying the analysis process.

Contribution

It introduces a direct inversion method for LEED I-V spectra to obtain Patterson functions and a new R-factor for objective structural discrimination.

Findings

Four out of six models were discarded using the Patterson analysis

The method reduces the parameter space for structural determination

The analysis requires specific data quality and quantity

Abstract

Surface Patterson Functions have been derived by direct inversion of experimental Low-Energy Electron Diffraction I-V spectra measured at multiple incident angles. The direct inversion is computationally simple and can be used to discriminate between different structural models. 1x1 YSi_2 epitaxial layers grown on Si(111) have been used to illustrate the analysis. We introduce a suitable R-factor for the Patterson Function to make the structural discrimination as objective as possible. From six competing models needed to complete the geometrical search, four could easily be discarded, achieving a very significant and useful reduction in the parameter space to be explored by standard dynamical LEED methods. The amount and quality of data needed for this analysis is discussed.